Specific features of the pyroelectric effect in epitaxial aluminum nitride layers obtained on Si substrates

The pyroeffect was studied in quasi-bulk AlN layers with a thickness of 10–170 $\mu$m obtained by the technology of chloride-hydride vapor phase epitaxy on standard Si sub-strates. The pyroelectric current was measured by the method of thermal exposure to non-stationary (me-ander type) laser radiation, that together with the data of independent non-contact measure-ment of the active layer surface temperature dynamics made it possible to determine the value of the pyroelectric coefficient AlN in the composition of the bimorph AlN/Si structure for different thicknesses of AlN layers. It was found that the mean values are less than those that correspond to the material obtained by the same technology, but on SiC substrates; so, in or-der to achieve the pyrocoefficients of comparable magnitude with those in the case of “AlN on Si”, an increase in the thickness of AlN layers by 60–70% is re-quired. At the same time, when the thickness of the AlN layer is large (110 $\mu$m, 170 $\mu$m) after the removal of the silicon substrate, the pyroelectric coefficient increased and reached $\sim$8.6–9.0 $\mu$C/(m$^2$K).